package com.javasee.common.utils;

import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

@Component
public class SpringContextUtils  implements ApplicationContextAware{
	private static ApplicationContext applicationContext;
	/**
	 * 实现ApplicationContextAware接口的context注入函数, 将其存入静态变量.
	 */
	public void setApplicationContext(ApplicationContext applicationContext) {
		if (SpringContextUtils.applicationContext == null) {
			SpringContextUtils.applicationContext = applicationContext;
		}
	}
 
	/**
	 * 取得存储在静态变量中的ApplicationContext.
	 */
	public static ApplicationContext getApplicationContext() {
		checkApplicationContext();
		return applicationContext;
	}
	
	/**
	 * 清除applicationContext静态变量.
	 */
	public static void cleanApplicationContext() {
		applicationContext = null;
	}
	
	private static void checkApplicationContext() {
		if (applicationContext == null) {
			throw new IllegalStateException("applicaitonContext未注入");
		}
	}
	
	/**
	 * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型.
	 */
	@SuppressWarnings("unchecked")
	public static <T> T getBean(String name) {
		checkApplicationContext();
		return (T) applicationContext.getBean(name);
	}
 
	/**
	 * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型.
	 */
	@SuppressWarnings("unchecked")
	public static <T> T getBean(Class<T> clazz) {
		checkApplicationContext();
		return (T) applicationContext.getBeansOfType(clazz);
	}
}